The present invention relates to a method of attaching a press-in flange to drums and like containers.
Conventionally a press-in flange is attached to a tubular mouthpiece on the top plate of a drum by fitting an annular gasket around the tubular portion of the flange, and forcing the flange into the mouthpiece of the top plate from below to fold the upper end of the tubular portion of the flange over the upper end of the mouthpiece and fit the outer periphery of a polygonal horizontal portion of the flange into pressing contact with the inner peripheral surface of a similarly polygonal skirt portion of the mouthpiece at the lower end thereof. However, when preparation of the flange or the top plate involves errors or if the horizontal portion is fitted in the skirt portion as displaced therefrom, a clearance occurs between the outer periphery of the horizontal portion and the skirt portion. Further when the gasket has great hardness or is confined in too small a space, the gasket pushes up the top plate to produce a clearance between the outer periphery of the horizontal portion and the skirt portion. Accordingly the contents of the drum seep through such a clearance to attack the gasket and to permit the gasket to partly come out through the clearance when swelling, impairing the sealing function of the gasket and resulting in a leak.